@mangar2/decision v2.3.1

Abstract

Provides a JSON based term evaluator to calculate decisions based on configuration files The syntax of the JSON-terms is derived from Lisp .

Contents

• Meta
• Class Decision
  • Parameters
  • Methods
    • _ISOStringToDate
    • eval
    • on
• Class EvalResult
  • Parameters
  • Members

Meta

Class Decision

new Decision(variables)

Creates a value class providing the ability to evalutate a json based value . Additionally it explains the value in a juman readable string . Supported operations are

• "or" , t1 , t2 , . . .
• "and" , t1 , t2 , . . .
• operator , t1 , t2 with operators '>' , '<' , '> = ' , '< = ' , ' ! = ' , ' = '
• "+/-" , t1 , t2
• "if" , t1 , then , else
• "switch" , t1 , { map } where map is an array of variable value maps . Example "switch" , 1 , { 1 : "a" , 2 : "b" } results in 'a'
• "function" , . . . parameter where function is registrated by a call to 'on'

Example

const variables = {
   'a/b': 1,
   'b/c': 2,
   'system/presence': 'awake'
}
const value = new Decision(variables)
const result = value.decide(
     [
          'and',
          ['or', ['<', 'a/b', 10], ['<', 'b/c', 2]],
          ['or', ['>=', 'a/b', 10], ['>=', 'b/c', 2]]
      ]
)
// returns result.value = true and result.reason = 'a/b (1) is < 10 and b/c (2) is >= 2'

Decision Parameters

Decision Methods

_ISOStringToDate

_ISOStringToDate (value) => {Date, any}

Converts any value from an ISO formatted date string to a date object If it is not an ISO formatted date string , the original value will be returned

_ISOStringToDate Parameters

_ISOStringToDate returns

eval

eval (jsonTree) => {EvalResult}

Calculates a value based on a json based json tree

eval Parameters

eval throws

eval returns

on

on (event, callback)

Sets a callback .

on Parameters

on throws

Class EvalResult

new EvalResult(value, reason)

Creates a result object with a "value" and a "reason" and a list of used variable : value pairs

EvalResult Parameters

EvalResult Members